The present invention relates to golf balls and, in particular, to golf balls components formed form compositions comprising lipid-based nanotubules for controlled release of a variety of compounds.
Golf balls can generally be divided into two classes: solid and wound. Solid golf balls include one-piece, two-piece (i.e., solid core and a cover), and multi-layer (i.e., solid core of one or more layers and/or a cover of one or more layers) golf balls. Wound golf balls typically include a solid, hollow, or fluid-filled center, surrounded by tensioned elastomeric material, and a cover. Solid balls have traditionally been considered not only longer and more durable than wound balls, but also lacking a particular xe2x80x9cfeelxe2x80x9d provided by the wound construction that was preferred by accomplished golfers.
By altering solid ball construction and composition, however, manufacturers have learned how to vary a wide range of playing characteristics, such as resilience, durability, spin, and xe2x80x9cfeel,xe2x80x9d each of which can be optimized for various playing abilities. This improvement in construction technology has allowed current solid golf balls to provide feel characteristics more like their wound predecessors. The golf ball components, in particular, that many manufacturers continually look to improve are the center or core, intermediate layers, if present, and covers.
Golf ball cores and/or centers are typically constructed with polybutadiene-based polymer compositions. Compositions of this type are constantly being altered in an effort to provide a higher coefficient of restitution (xe2x80x9cCORxe2x80x9d) while concurrently lowering compression which, in turn, can lower the golf ball spin rate, provide better xe2x80x9cfeel,xe2x80x9d or both.
Manufacturers also address the properties and construction of golf ball intermediate and cover layers. These layers have conventionally been formed of ionomers and ionomer blends of varying hardness and flexural moduli. The hardness range of ionomers is limited and even the softest blends can suffer from a xe2x80x9cplasticxe2x80x9d feel. Recently, however, polyurethane-based materials have been employed in golf ball layers and, in particular, outer cover layers, due to their softer xe2x80x9cfeelxe2x80x9d characteristics, without a noticeable loss in resiliency and/or durability.
There remains a need, however, for improved golf ball center, core, layer, cover, and coating materials. Therefore, the present invention is directed to the use of novel, lipid-based nanotubules blended into the polymers or coatings/adhesives from which golf ball components are formed. The nanotubules are xe2x80x9cloadedxe2x80x9d (filled) with active agents, such as UV absorbers, light stabilizers, bleaching agents, dyes, fluorophores, and/or healing agents, to name a few, for the controlled release of these compounds during the life of the golf ball. It is envisioned that certain compounds may be selected that can prolong the useful life and performance of a golf ball because they are being xe2x80x9creplentishedxe2x80x9d as a function of time.
The present invention is directed to a golf ball comprising a core; and a cover layer disposed concentrically about the core; wherein at least one of the core or the cover is formed of a polymer comprising lipid-based nanotubules in which an active compound is microencapsulated. In one embodiment, the cover includes the lipid-based nanotubules. The cover can be an outer core layer, an inner cover layer, or an outer cover layer. The core may be a single layer or include a center and an outer core layer. Either may include the lipid-based nanotubules of the present invention. In a preferred embodiment, the center and/or core composition includes an organosulfur compound. Preferably, the core has an outer diameter of between about 1.5 inches and about 1.62 inches and the cover layer preferably includes an inner cover layer and an outer cover layer, at least one of which contains the lipid-based nanotubules.
The polymer containing the nanotubules thermoplastics, thermosets, ionomers, non-ionomers, polysaccharides; polyesters; polyamides; polypeptides; polyurethanes; polyureas, polyethylenes; polypropylenes; polyvinylchlorides; polystyrenes; polyphenols; polyvinyl pyrollidones; polyvinyl alcohols; ethylcelluloses; gar gums; metallocene-catalyzed polymers; polyvinyl formal resins; water soluble epoxy resins; urea-formaldehydes; polylysines; chitosans; polyvinyl acetates; and polymers containing xcex1, xcex2-unsaturated carboxylic acid groups, or the salts thereof.
Preferably, the acid groups have been 100% neutralized by an organic acid or a salt, a cation source, or a suitable base thereof. In a preferred embodiment, the active compound has a diameter and the nanotubules have an inner diameter between about 2 to about 1000 times the diameter of the active compound. Ideally, the nanotubule has an inner diameter between about 20 to about 500 times the diameter of the active compound. The nanotubules are preferably configured to release the active compound at a constant rate. Additoinally, the nanotubules may further include a solubility modifier in an amount sufficient to alter the rate of release of the active compound. The active compound should have a sufficiently low viscosity to facilitate loading the nanotubules by capillary action. The active compound may also include UV absorbers, light stabilizers, bleaching agents, fluorophores, healing agents, catalysts, reactive identifiers, inks, dyes, and indicators.
In one embodiment, the nanotubules have an inner diameter of from about 50 nm to about 20 xcexcm and, more preferably, from about 100 nm to about 1 xcexcm, and most preferably, from about 200 nm to about 800 nm. In another embodiment, the nanotubules have a length of from about 1 xcexcm to about 1 mm, more preferably, from about 10 xcexcm to about 200 xcexcm. The polymer that contains the nanotubules preferably includes between about 5% and about 70% nanotubules.
In another embodiment, a coating layer including the nanotubules is present. The coating may be formed from paints, primers, adhesives, urethanes, epoxies, or dyes and can be applied by roller, brush, dipping, or spray.
The cover layer is formed by compression molding, injection molding, casting, or reaction injection molding. Preferably, the cover layer is an outer cover layer and includes polyureas, polyurethanes, polyurethane-ureas, polyurea-urethanes, or epoxies. Ideally, the polyureas, polyurethanes, polyurethane-ureas, polyurea-urethanes, or epoxies are aliphatic or saturated. In an alternative embodiment, the golf ball has a coefficient of restitution of greater than about 0.8.
The present invention is also directed to a golf ball comprising a core; an intermediate layer disposed about the core; a cover disposed about the intermediate layer; and a coating layer; wherein the cover is comprised of lipid-based nanotubules comprising UV absorbers, light stabilizers, bleaching agents, fluorophores, healing agents, catalysts, reactive identifiers, inks, dyes, or indicators for controlled release into at least one of the adjacent intermediate or coating layers.
The present invention is further directed to a golf ball comprising a core; and a cover layer disposed concentrically about the core; wherein at least one of the core or the cover is formed of a polymer comprising lipid-based nanotubules.